title: Mitochondrial reactive oxygen species promote p65 nuclear translocation mediating high-phosphate-induced vascular calcification in vitro and in vivo.
abstract: Hyperphosphatemia is the major risk factor associated with vascular calcification (VC) in end-stage renal disease. As oxidative stress is increased in uremia, we studied the role of mitochondrial reactive oxygen species (ROS) and nuclear factor-κB signaling in phosphate-induced VC. In an in vitro calcification model (β-glycerophosphate (BGP) induction) using bovine aortic smooth muscle cells, the production of intracellular and mitochondrial ROS, or superoxide anion, was stimulated by increased mitochondrial membrane potential. This effect was blocked by the superoxide dismutase (SOD) mimic MnTMPyP, a respiratory chain inhibitor rotenone, or a protonophore. Calcium deposition and the switch of smooth muscle cells from a contractile to an osteogenic phenotype were decreased when mitochondrial ROS generation was inhibited by the respiratory chain inhibitor, MnTMPyP, or the overexpression of SOD1 and SOD2 and uncoupling protein 2. The phosphorylation of IkKβ, IκBα degradation, and p65 nuclear translocation were increased by BGP but reversed when mitochondrial ROS production was blocked by protonophore or MnTMPyP. Knockdown of endogenous p65 or overexpression of IκBα reduced calcium deposition in the cultured cells. Furthermore, in a rat model of dietary adenine-induced chronic renal failure, MnTMPyP reduced aortic ROS levels, p65 activation, and calcium deposition. Thus, mitochondrial ROS-mediated p65 nuclear translocation is involved in phosphate-induced VC.
authors.affiliation: Department of Physiology and Pathophysiology, School of Basic Medical Science, Peking University Health Science Center, Beijing, People's Republic of China.
authors.forename: Ming-Ming
authors.initials: MM
authors.lastname: Zhao
authors.forename: Ming-Jiang
authors.initials: MJ
authors.lastname: Xu
authors.forename: Yan
authors.initials: Y
authors.lastname: Cai
authors.forename: Gexin
authors.initials: G
authors.lastname: Zhao
authors.forename: Youfei
authors.initials: Y
authors.lastname: Guan
authors.forename: Wei
authors.initials: W
authors.lastname: Kong
authors.forename: Chaoshu
authors.initials: C
authors.lastname: Tang
authors.forename: Xian
authors.initials: X
authors.lastname: Wang
mesh_terms: D021581:Active Transport, Cell Nucleus; D000818:Animals; D002114:Calcinosis / Q000209:etiology*; D002478:Cells, Cultured; D005994:Glycerophosphates / Q000494:pharmacology; D008297:Male; D053078:Membrane Potential, Mitochondrial; D008665:Metalloporphyrins / Q000494:pharmacology; D008928:Mitochondria / Q000378:metabolism*; D009131:Muscle, Smooth, Vascular / Q000473:pathology; D032389:Myocytes, Smooth Muscle / Q000473:pathology; D010710:Phosphates / Q000633:toxicity*; D051381:Rats; D017208:Rats, Wistar; D017382:Reactive Oxygen Species / Q000378:metabolism*; D051996:Transcription Factor RelA / Q000378:metabolism*; D014652:Vascular Diseases / Q000209:etiology*
chemical_list: D005994:Glycerophosphates; D008665:Metalloporphyrins; C502230:Mn(III) 5,10,15,20-tetrakis(N-methylpyridinium-2-yl)porphyrin; D010710:Phosphates; D017382:Reactive Oxygen Species; D051996:Transcription Factor RelA; C031463:beta-glycerophosphoric acid